The Total solution for NCERT class 6-12
4(x – y)2 – 12(x – y) (x + y) + 9(x + y)2= [2(x – y)2 + 2 x 2(x – y) x 3(x + y) + [3 (x+y]2 {∵ a2 + b2 +2 abc = (a + b)2}= [2(x – y) + 3(x + y)]2= (2x-2y + 3x + 3y)2= (5x + y)2